In general, an α-olefin low polymer is produced according to a method of low polymerization reaction of an α-olefin in the presence of a catalyst and a solvent. For example, JP-A 8-134131 discloses a method for producing 1-hexene through trimerization of ethylene in the presence of a catalyst containing a chromium compound and a halogen-containing compound and a solvent, and discloses halides of linear hydrocarbons as the halogen-containing compound (PTL 1).
JP-A 2008-179801 discloses that 1-hexene as a raw material for polyethylene production, which is produced through trimerization of ethylene in the presence of a catalyst containing a chromium compound and a halogen-containing compound contains a halogenated olefin that is generated as a side product in decomposition of the halogen-containing compound (PTL 2).